Failed to solve the following constraints:
  _10 := refl [blocked on problem 12]
  [12, 16] ?0 a x x₁ = ?0 b x x₁ : A
Unsolved metas at the following locations:
  Issue3114.agda:13,7-11
Unsolved interaction metas at the following locations:
  Issue3114.agda:10,10-11
